According to a September 1, 2022 blog post, Microsoft will allow a one time extension through 12/31/2022 users who have not yet met the requirement to use OAuth for more secure login to MAPI, RPC, Offline Address Book (OAB), Exchange Web Services (EWS), POP, IMAP, Exchange ActiveSync (EAS), and Remote PowerShell.

Furthermore, in a 9-9-2022 blog post Microsoft clarifies that SMTP AUTH will NOT be disabled for active users of the authentication method. The company does urge users to adopt OAuth as a more secure method but clarifies that SMTP AUTH is not shutting down. At least not as of 9/9/2022.

From Microsoft blog post 9-1-2022
One-Time Re-Enablement
Today we are announcing an update to our plan to offer customers who are unaware or are not ready for this change.
When we turn off basic auth after October 1st, all customers will be able to use the self-service diagnostic to re-enable basic auth for any protocols they need, once per protocol. Details on this process are below.
Once this diagnostic is run, basic auth will be re-enabled for those protocol(s). Selected protocol(s) will stay enabled for basic auth use until end of December 2022. During the first week of calendar year 2023, those protocols will be disabled for basic auth use permanently, and there will be no possibility of using basic auth after that.